Blockage of the flow of genetic information by complementary base-pairing has been designated as "anti-sense" inhibition. This proposal addresses the use of anti-sense RNAs to inhibit replication and expression of the etiological agent of AIDS, the HIV virus. A major focus of this proposal is the use of anti-sense RNAs with enzymatic activities, or ribozymes, for the disruption of HIV function. Anti-HIV ribozymes have been shown to cleave specific targets within the viral genome, thereby functionally inactivating the virus. The proposed research will capitalize upon these findings for the development of ribozymes as potent anti-HIV agents in an intracellular environment. To accomplish this, experiments are proposed to: 1) develop an assay system which will allow the measurement of intracellular activity of ribozymes as well as the metabolic fates of both the cleaved substrate and ribozymes; 2) identify targets within HIV-1 genome which will be maximally accessible to ribozyme cleavage and hence functional inactivation of the virus, yet minimally subject to genetic variability; 3) develop intracellular expression systems which maximize anti-sense and ribozyme RNA expression in particular intracellular compartments. In conjunction with development of ribozymes for AIDS therapies, we will further explore the potential effectiveness of non- enzymatic, or standard anti-sense transcripts in the functional inhibition of HIV expression and replication. The long range goal of this research is the development of a ribozyme (anti-sense) therapy for the prevention and treatment of HIV infection.